The combustion of fossil fuels to generate energy has resulted in a large increase in the proportion of carbon dioxide in the Earth's atmosphere in recent decades, wherein the concentration of carbon dioxide in the Earth's atmosphere has increased by almost 40% since the start of industrialization. Furthermore it is believed that the emission of carbon dioxide accounts for approximately 60% of the greenhouse effect caused by humans. In order to counteract further global warming, it is therefore imperative that the emission of carbon dioxide into the Earth's atmosphere be reduced as much as possible. As a large part of global carbon dioxide emissions are caused by the combustion of fossil fuels in coal-fired power stations, a huge savings potential for reducing global carbon dioxide emissions is to be found here.
Various processes for reducing the carbon dioxide emitted are already used in large-scale process engineering. So-called membrane separation processes in which the substance mixture to be separated, e.g. the flue gas of a power station, is separated into a retentate stream and a permeate stream by means of a membrane appear to be particularly advantageous. The stream which penetrates the membrane and is thus separated from the feed material is called the permeate stream. The stream stripped of the permeate, which does not penetrate the membrane and leaves the separation unit, is called the retentate stream. Using renewable energy, the carbon dioxide separated off as permeate can then be converted into usable, carbon-based products such as fuels or polymers, or can be stored underground or used as nutrient for algae.
In order to provide the membrane surface area necessary for removing carbon dioxide from the flue gas of a power station, relatively small membrane modules are currently used in large numbers. For example, approximately 6,000 standard membrane modules, each with an effective membrane surface area of 100 m2, are necessary to remove the carbon dioxide from the flue gas of a hard-coal-fired power station with a capacity of 1500 MW. However, the individual membrane modules must be equipped with the corresponding control valves and tubing, which makes the process very error-prone, maintenance-intensive and expensive. It would therefore be desirable to use a small number of comparatively large membrane modules. However, it is currently very laborious and expensive to handle and, above all, transport large membrane modules, because of the comparatively large volume and high weight. Comparatively large membrane modules have therefore not come into use yet.